From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean-Jacques Hiblot Date: Mon, 9 Apr 2018 15:58:05 +0200 Subject: [U-Boot] [BUG] snow: mmc: SD card access broken: unable to select a mode In-Reply-To: References: Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: u-boot@lists.denx.de On 09/04/2018 14:02, Guillaume Gardet wrote: > Hi Jaehoon, > > There are problems with SD card access on Samsung Chromebook (snow) > with latest master (and also 2018.05-rc1 and 2018.03). > > eMMC is ok, but SD card access leads to 'unable to select a mode' > problem. If I disable HS mode, I can access the SD card without problem: > ******************************************************************************** > > diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c > index 23f642980bf..28f4fa0f213 100644 > --- a/drivers/mmc/dw_mmc.c > +++ b/drivers/mmc/dw_mmc.c > @@ -508,7 +508,8 @@ void dwmci_setup_cfg(struct mmc_config *cfg, > struct dwmci_host *host, >          cfg->host_caps |= MMC_MODE_4BIT; >          cfg->host_caps &= ~MMC_MODE_8BIT; >      } > -    cfg->host_caps |= MMC_MODE_HS | MMC_MODE_HS_52MHz; > +    /* Temp workaround for Chromebook snow to avoid the 'unable to > select a mode' error */ > +//     cfg->host_caps |= MMC_MODE_HS | MMC_MODE_HS_52MHz; > >      cfg->b_max = CONFIG_SYS_MMC_MAX_BLK_COUNT; >  } > ******************************************************************************** > > > Once we try to select HS mode, all access to SD card result in > failure, even when trying to setup a lower frequency mode, including > SD legacy at 25 MHz. > > Any idea what is going? Maybe you have fixes pending? Can try with MMC_MODE_HS | MMC_MODE_HS_52MHz but with a lower max-frequency (<25MHz) ? It would be interesting to know if it could come from a frequency limitation. Is there some pad configuration to do when using higher frequency? JJ > > > Guillaume > > >